Pneumatic Tire

Abstract

A pneumatic tire is provided with, in the tread surface, a land portion that is a rib or a plurality of blocks. The plurality of blocks are each provided with a plurality of narrow shallow grooves and a plurality of recessed portions that communicate with the plurality of narrow shallow grooves in a contact patch. The recessed portions are disposed across separate adjacent narrow shallow grooves. The narrow shallow grooves each have a groove width of from 0.2 mm to 0.7 mm and a groove depth from 0.2 mm to 0.7 mm. The recessed portions each have the same depth as the narrow shallow grooves.

1 . A pneumatic tire comprising in a tread surface thereof a land portion that is a rib or a row of blocks,
 the land portion comprising in a contact patch thereof a plurality of narrow shallow grooves and a plurality of recessed portions that communicate with the narrow shallow grooves, and   the plurality of recessed portions are disposed across separate adjacent narrow shallow grooves of the plurality of narrow shallow grooves.   
     
     
         2 . The pneumatic tire according to  claim 1 , wherein a disposal density Da of the plurality of recessed portions in an entire region of a continuous contact patch of the land portion is in a range 0.8 unit/cm 2 ≤Da≤4.0 unit/cm 2 . 
     
     
         3 . The pneumatic tire according to  claim 1 , wherein
 the land portion comprises in the contact patch thereof a plurality of sipes, and   the plurality of recessed portions are disposed spaced apart from the sipes.   
     
     
         4 . The pneumatic tire according to  claim 1 , wherein
 the land portion comprises in the contact patch thereof a plurality of sipes that partition the plurality of narrow shallow grooves, a portion of one of the plurality of narrow shallow grooves that partition the plurality of sipes extends without penetrating through two or more of the plurality of recessed portions.   
     
     
         5 . The pneumatic tire according to  claim 1 , wherein
 a plurality of sipes are disposed side by side and divide the land portion into a plurality of sections in a tire circumferential direction, and   a section comprising the recessed portion only in a central region in a tire lateral direction and a section comprising the recessed portion in only either of end portion regions in the tire lateral direction are disposed alternately in the tire circumferential direction.   
     
     
         6 . The pneumatic tire according to  claim 1 , wherein
 a plurality of sipes are disposed side by side in a tire circumferential direction and divide the land portion into a plurality of sections, and   at least one of two discretionary adjacent sections of the plurality of sections comprises the recessed portions in end portion regions in a tire lateral direction.   
     
     
         7 . The pneumatic tire according to  claim 1 , wherein
 a plurality of sipes are disposed side by side in a tire circumferential direction and divide the land portion into a plurality of sections, and   three discretionary sections adjacent in a tire lateral direction of the plurality of sections comprise a section comprising the recessed portion in either of end portion regions in the tire lateral direction and a section comprising the recessed portion in a central region in the tire lateral direction.   
     
     
         8 . The pneumatic tire according to  claim 1 , wherein
 a plurality of sipes are disposed side by side in a tire circumferential direction and divide the land portion into a plurality of sections, and   three discretionary sections adjacent in a tire lateral direction of the plurality of sections comprise a section comprising the recessed portion and a section without the recessed portion.   
     
     
         9 . The pneumatic tire according to  claim 1 , wherein
 the land portion is a row of blocks that comprises a plurality of blocks, and   the recessed portions are disposed in corner portions of the blocks.   
     
     
         10 . The pneumatic tire according to  claim 1 , wherein
 the land portion is a row of blocks that comprises a plurality of blocks, and   the recessed portions are not disposed in end portions of the blocks in a tire circumferential direction or a central region of the blocks in a tire lateral direction.   
     
     
         11 . The pneumatic tire according to  claim 1 , wherein an opening area of the recessed portions ranges from 2.5 mm 2  to 10 mm 2 . 
     
     
         12 . The pneumatic tire according to  claim 1 , wherein the recessed portions have a circular or elliptical shape at the contact patch of the land portion. 
     
     
         13 . The pneumatic tire according to  claim 1 , wherein a wall angle α of the recessed portions is in a range −85 degrees≤α≤95 degrees. 
     
     
         14 . The pneumatic tire according to  claim 1 , wherein a depth Hd of the recessed portions and a groove depth Hg of the narrow shallow grooves have a relationship 0.5≤Hd/Hg≤1.5. 
     
     
         15 . The pneumatic tire according to  claim 1 , wherein at least one of the recessed portions is disposed at a position corresponding to a vent hole of a tire mold.